The present invention relates to a receptacle arrangement for an air bag, and, more particularly, to an arrangement in which lateral covering flaps and subsequently the entire covering can be swivelled back from the container aperture about a bottom transverse hinge.
U.S. Pat. No. 3,794,349 describes a covering for an air bag which is fixed to a base plate of an instrument panel and covers an air bag container. By virtue of a slot-type notching in the covering profile, the covering has in a lower edge region a transverse hinge, about which the covering can be folded back against the vehicle floor during the unfolding of the air bag. The air bag, which is inflated by a gas generator in fractions of a second, presses against the inside of the covering with great force, by which the covering is burst open and the air bag fabric emerges at great speed in the direction of a vehicle occupant.
An underlying object of the present invention is to reduce the momentum of an air bag when it is unfolding from a covering in the direction of a vehicle occupant.
The object has been achieved by a receptacle arrangement for an air bag which protects a vehicle occupant from an impact onto parts of the vehicle interior, having a rectangular covering. The long rectangular sides of the covering are aligned in the transverse direction of the vehicle in straight-ahead travel, and which, fixed to a base plate, covers an air bag container and folds out along a transverse hinge axis of a hinge in the lower edge region of the air bag container during the unfolding of the air bag, after which it completely exposes a container aperture above the edge region for the passage of the bag fabric into an inflated position in front of the vehicle occupant. The covering has, in addition to the first bottom transverse hinge, two further hinges which bound the first hinge on both sides, are approximately perpendicular thereto and have a clearance from the lateral edges of the covering. Thereby two lateral covering flaps are formed which subdivide the swivellable covering, and firstly the lateral covering flaps and subsequently the entire covering can be swivelled back from the container aperture about the bottom transverse hinge due to a loading of the inside of the covering by the unfolding air bag.
During the unfolding of the air bag the lateral covering flaps of the covering open from the lateral regions of the air bag container first, which means that the air bag has already attained a certain filling volume before the entire covering folds back from the container aperture. Thus, the movement of the air bag in the central region is retarded in relation to the side regions. The unfolding momentum of the very rapidly unfolding air bag is thereby diminished in the central region of the air bag.
This opening mechanism can not only be controlled by the method of folding the air bag into the air bag container, but also by controlling a sequence of this type by providing additional control-related connections of the covering to the triggering mechanism of the gas generator. The predetermined break edges around the lateral covering flaps can be machined deeper into the covering material than the predetermined break edge which, as the last one, releases a swivel movement of the complete covering, and/or the hinges of the swivellable covering and the two lateral covering flaps are provided such that the covering, which can be swivelled back last, has in the hinge a higher resistance to the opening movement than the hinges of the lateral covering flaps. This resistance can be influenced by an insert strip attached to the inside of the covering.
If the air bag container with the fold-out covering is fixed in a steering wheel, it is advantageous to arrange it in such a way that it does not project over the steering wheel hub after the air bag has unfolded.